diff options
Diffstat (limited to 'security/selinux/ss/services.c')
| -rw-r--r-- | security/selinux/ss/services.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 8ee04a424df7..7f0ee1b91e1d 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -2054,6 +2054,91 @@ out: return rc; } +/** + * security_net_peersid_resolve - Compare and resolve two network peer SIDs + * @nlbl_sid: NetLabel SID + * @nlbl_type: NetLabel labeling protocol type + * @xfrm_sid: XFRM SID + * + * Description: + * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be + * resolved into a single SID it is returned via @peer_sid and the function + * returns zero. Otherwise @peer_sid is set to SECSID_NULL and the function + * returns a negative value. A table summarizing the behavior is below: + * + * | function return | @sid + * ------------------------------+-----------------+----------------- + * no peer labels | 0 | SECSID_NULL + * single peer label | 0 | <peer_label> + * multiple, consistent labels | 0 | <peer_label> + * multiple, inconsistent labels | -<errno> | SECSID_NULL + * + */ +int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type, + u32 xfrm_sid, + u32 *peer_sid) +{ + int rc; + struct context *nlbl_ctx; + struct context *xfrm_ctx; + + /* handle the common (which also happens to be the set of easy) cases + * right away, these two if statements catch everything involving a + * single or absent peer SID/label */ + if (xfrm_sid == SECSID_NULL) { + *peer_sid = nlbl_sid; + return 0; + } + /* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label + * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label + * is present */ + if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) { + *peer_sid = xfrm_sid; + return 0; + } + + /* we don't need to check ss_initialized here since the only way both + * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the + * security server was initialized and ss_initialized was true */ + if (!selinux_mls_enabled) { + *peer_sid = SECSID_NULL; + return 0; + } + + POLICY_RDLOCK; + + nlbl_ctx = sidtab_search(&sidtab, nlbl_sid); + if (!nlbl_ctx) { + printk(KERN_ERR + "security_sid_mls_cmp: unrecognized SID %d\n", + nlbl_sid); + rc = -EINVAL; + goto out_slowpath; + } + xfrm_ctx = sidtab_search(&sidtab, xfrm_sid); + if (!xfrm_ctx) { + printk(KERN_ERR + "security_sid_mls_cmp: unrecognized SID %d\n", + xfrm_sid); + rc = -EINVAL; + goto out_slowpath; + } + rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES); + +out_slowpath: + POLICY_RDUNLOCK; + if (rc == 0) + /* at present NetLabel SIDs/labels really only carry MLS + * information so if the MLS portion of the NetLabel SID + * matches the MLS portion of the labeled XFRM SID/label + * then pass along the XFRM SID as it is the most + * expressive */ + *peer_sid = xfrm_sid; + else + *peer_sid = SECSID_NULL; + return rc; +} + static int get_classes_callback(void *k, void *d, void *args) { struct class_datum *datum = d; |